The applicant has previously proposed a power feeding system for a solenoid valve assembly in Japanese patent application No. 2006-337528. The proposed solenoid valve assembly includes a solenoid valve body having a passage switching section and a solenoid operation section for operating the passage switching section, and a power feeding system for feeding the solenoid operation section with power, the power feeding system being provided with a printed circuit board inside a terminal cover mounted at the side of the solenoid valve body. Both of the front and back sides of the printed circuit board have a pin-shaped relay terminal to be inserted into a socket-shaped relay terminal electrically connected with the solenoid operation section, and pin-shaped power receiving terminals to be inserted into a power feeding socket mounted at the tip of a feeding line, the relay terminals and power receiving terminals feeding electrical power from the power feeding socket to the solenoid operation section therethrough.
Although the proposed solenoid valve assembly mentioned above assumes that the solenoid valve assembly is provided with the above-mentioned printed circuit board connected with electronic components having a surge protection circuit for controlling power feeding and a power saving circuit, and the like, there may be no need for the printed circuit board mentioned above if power feeding is controlled from external equipment. If so, a solenoid valve assembly equipped with no printed circuit board may be needed. If solenoid valve assemblies equipped with the printed circuit board are to be volume-produced as general-purpose items, it is desirable for solenoid valve assemblies with no printed circuit board to use the same solenoid valve body as those with the printed circuit board and to have a power feeding system of a modified design for the purposes of marketing solenoid valves at lower prices.
However, if the printed circuit board is omitted from the solenoid valve assembly, a modification must be made to the socket-shaped power feeding terminal at the tip of feeding lines to form a pin-shaped terminal so as to allow direct connection with the socket-shaped relay terminal mounted on the solenoid valve body for successful power feeding. In order to ensure safety, the power feeding system must be reconfigured, so as to avoid an exposure of the pin-shaped power feeding terminal to the outside of the assembly when it is unexpectedly disconnected from the relay terminal mounted on the solenoid valve body after they are connected to each other.